Nuclear power station equipment cooling water waste heat recovery system and use method

Abstract

The invention relates to the technical field of nuclear power station waste heat utilization, in particular to a nuclear power station equipment cooling water waste heat recovery system and a use method. A nuclear power station equipment cooling water waste heat recovery system comprises a water supply assembly which comprises a water supply main pipeline, one end of the water supply main pipeline is suitable for being communicated with a waste heat outflow pipeline through a first communication port, the other end of the water supply main pipeline is suitable for being communicated with a water inlet of a user assembly, and water flows in the waste heat outflow pipeline; the first heating assembly comprises a first heating pump set, and the first heating pump set is arranged on the water supply main pipeline; and the water return assembly comprises a water return main pipeline, one end of the water return main pipeline is suitable for communicating with the waste heat outflow pipeline through the second communicating port, and the other end is suitable for communicating with the water outlet of the user assembly. The invention provides a nuclear power station equipment cooling water waste heat recovery system and a use method, and aims to solve the problem that the temperature of water flow generated by an equipment cooling water system of a nuclear power station is too high when the water flow is discharged into the sea.

Description

Technical Field

[0001] The present invention relates to the technical field of waste heat utilization in nuclear power plants, and particularly relates to a waste heat recovery system and a usage method for the cooling water of nuclear power plant equipment. Background Art

[0002] The main heat users in nuclear power plants include nuclear island users, conventional island and BOP sub-item heating users, and seawater desalination process users. The heat supply gas source in the power station is mainly through main steam or auxiliary boilers. By utilizing relatively high steam parameters of the steam turbine, 95°C heating hot water is obtained, and there are relatively large irreversible losses in this heat transfer process, having a certain energy-saving space. If waste heat is used for heating, the steam extraction volume can be reduced, the steam utilization rate of the power plant can be decreased, and high-quality steam can be saved.

[0003] There are many process users in the nuclear island of the nuclear power plant that need to discharge heat. For example, the main function of the equipment cooling water system is to take out the heat of the heat exchangers of each process system in the nuclear island, and transfer the heat load to the ultimate heat sink - seawater through the plate heat exchanger set in the equipment cooling water system. During the heating season, due to the discharge of warm wastewater, the seawater temperature rises. Generally, the sea areas with temperature rise will have a certain impact on the types of aquatic organisms and the seawater aquaculture industry. Summary of the Invention

[0004] In view of this, the present invention provides a waste heat recovery system and a usage method for the cooling water of nuclear power plant equipment to solve the problem that in winter, the water flow generated by the cooling water system of the nuclear power plant is at a relatively high temperature when discharged into the sea, which will increase the temperature in the drainage area and have an adverse impact on aquatic organisms and the seawater aquaculture industry.

[0005] In a first aspect, the present invention provides a waste heat recovery system for the cooling water of nuclear power plant equipment, including:

[0006] A water supply component, the water supply component includes a water supply main pipeline, one end of the water supply main pipeline is adapted to be communicated with a waste heat outflow pipeline through a first communication port, the other end of the water supply main pipeline is adapted to be communicated with the water inlet of a user component, and there is a water flow flowing in the waste heat outflow pipeline;

[0007] A first heating component, the first heating component includes a first heating pump group, and the first heating pump group is arranged on the water supply main pipeline;

[0008] A return water component, the return water component includes a return water main pipeline, one end of the return water main pipeline is adapted to be communicated with the waste heat outflow pipeline through a second communication port, the other end of the return water main pipeline is adapted to be communicated with the water outlet of the user component, the first communication port is located upstream of the second communication port, and a first control valve is arranged on the waste heat outflow pipeline between the first communication port and the second communication port.

[0009] During the heating season, the first control valve is closed, and the water flow at the first temperature in the waste heat outflow pipeline flows through the first water supply main pipeline into the first heating pump group. After the water flow at the second temperature heated by the first heating pump group flows through the first water supply main pipeline into the user assembly, after the user assembly extracts heat, the water flow at the third temperature flows back into the waste heat outflow pipeline through the return water main pipeline. The third temperature is lower than the first temperature until it is discharged into the sea through the drain outlet of the waste heat outflow pipeline, and the drain outlet is located downstream of the second communication port and is connected to the sea. By setting the first heating component, in winter, the temperature of the water flow in the waste heat outflow pipeline is heated, which facilitates the heating of the user assembly with the water flow at the second temperature. After the water flow after the user assembly warms up becomes the third temperature, since the third temperature is lower than the first temperature, the waste heat reuse of the water flow is realized, and the water temperature finally flowing into the sea is lower than the initial water temperature in the waste heat outflow pipeline, avoiding the discharge of warm drainage of the initial water flow in the waste heat outflow pipeline and preventing the increase of the water temperature in the waters at the drain outlet.

[0010] In an alternative embodiment, the water supply assembly includes a booster pump and a first switching valve. The water supply main pipeline includes a first water supply branch and a second water supply branch. A first switching valve is provided between the first water supply branch and the second water supply branch. The first heating component includes a first water inlet pipeline. The first water supply branch is located between the waste heat outflow pipeline and the first switching valve. A first water inlet pipeline is provided between the first heating pump group and the first switching valve.

[0011] In an alternative embodiment, the water supply assembly further includes an intermediate heat storage tank. The water supply main pipeline includes a third water supply branch. The first heating component includes a first water outlet pipeline. The second water supply branch is provided between the first switching valve and the intermediate heat storage tank. The first water outlet pipeline is provided between the first heating pump group and the intermediate heat storage tank. The third water supply branch is provided between the intermediate heat storage tank and the user assembly.

[0012] In an alternative embodiment, a second heating component is further included. The second heating component is communicated with the water supply main pipeline, and the first heating component is located upstream of the second heating component.

[0013] In an alternative embodiment, the second heating component includes a second heating pump group, a second water inlet pipeline, and a second water outlet pipeline. The second water inlet pipeline is respectively communicated with the water supply main pipeline and the second heating pump group. The second water outlet pipeline is respectively communicated with the water supply main pipeline and the second heating pump group. The connection of the second water inlet pipeline and the water supply main pipeline is located upstream of the connection of the second water outlet pipeline and the water supply main pipeline. The connection of the second water outlet pipeline and the water supply main pipeline is located upstream of the connection of the second water inlet pipeline and the water supply main pipeline.

[0014] In an alternative embodiment, the return water assembly further includes a circulation pump, a second control valve, and a second switching valve. The circulation pump, the second control valve, and the second switching valve are sequentially arranged on the return water main pipeline from the user assembly towards the waste heat outflow pipeline.

[0015] In an alternative embodiment, the first heating assembly further includes a third water inlet pipeline and a third water outlet pipeline. The third water inlet pipeline is arranged between the second switching valve and the first heating pump group, and the third water outlet pipeline is arranged between the first heating pump group and the return water main pipeline.

[0016] In an alternative embodiment, the second heating assembly further includes a fourth water inlet pipeline and a fourth water outlet pipeline. The fourth water inlet pipeline is arranged between the return water main pipeline and the second heating pump group, and the fourth water outlet pipeline is arranged between the return water main pipeline and the second heating pump group. The connection point of the fourth water inlet pipeline and the return water main pipeline is located upstream of the connection point of the fourth water outlet pipeline and the return water main pipeline.

[0017] In an alternative embodiment, it further includes a cold water heat exchange plate group. The waste heat outflow pipeline is provided with the cold water heat exchange plate group, and the cold water heat exchange plate group is provided at the water outlet port of the second communication port and the waste heat outflow pipeline. The cold water heat exchange plate group is adapted to be connected to the equipment cooling water supply pipeline.

[0018] In a second aspect, the present invention further provides a usage method of a waste heat recovery system for nuclear power plant equipment cooling water. During the heating season, the first control valve is closed, so that the water flow at the first temperature in the waste heat outflow pipeline flows through the first water supply main pipeline into the first heating pump group. After the water flow at the second temperature heated by the first heating pump group flows through the first water supply main pipeline into the user assembly, after the user assembly extracts heat, the water flow at the third temperature flows through the return water main pipeline and then into the waste heat outflow pipeline. The third temperature is less than the first temperature until it is discharged. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for use in the description of the specific embodiments or the prior art. Obviously, the following drawings are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0020] Figure 1 It is a schematic diagram of a waste heat recovery system for nuclear power plant equipment cooling water according to an embodiment of the present invention;

[0021] Figure 2 It is a schematic diagram of the water flow movement according to the first embodiment of the present invention;

[0022] Figure 3 Schematic diagram of the water flow movement of the second embodiment of the present invention;

[0023] Figure 4 Schematic diagram of the water flow movement of the third embodiment of the present invention.

[0024] Description of the reference numerals in the drawings: 1. Water supply assembly; 101. Main water supply pipeline; 1011. First water supply branch; 1012. Second water supply branch; 1013. Third water supply branch; 102. Third control valve; 103. Intermediate heat storage tank; 104. Booster pump; 105. First switching valve; 2. Return water assembly; 201. Main return water pipeline; 2011. First return water branch; 2012. Second return water branch; 2013. Third return water branch; 202. Circulation pump; 203. Second switching valve; 204. Second control valve; 3. First heating assembly; 301. First water inlet pipeline; 302. First water outlet pipeline; 303. First heating pump group; 304. Third water inlet pipeline; 305. Third water outlet pipeline; 306. First water outlet valve; 4. Second heating assembly; 401. Second water inlet pipeline; 402. Second water outlet pipeline; 403. Second heating pump group; 404. Fourth water inlet pipeline; 405. Fourth water outlet pipeline; 406. Fourth water inlet valve; 407. Intermediate pump; 5. User assembly; 6. Waste heat outflow pipeline; 601. First control valve; 602. Drainage port; 7. Heat exchange plate group; 8. Equipment cooling water supply pipeline; 9. First make-up water pipeline; 10. Second make-up water pipeline. Detailed implementation manners

[0025] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Apparently, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0026] The following will be combined with Figures 1 to 4 , to describe the embodiments of the present invention.

[0027] According to an embodiment of the present invention, on the one hand, a waste heat recovery system for cooling water of nuclear power plant equipment is provided, including: a water supply component 1, including a water supply main pipeline 101, one end of the water supply main pipeline 101 is adapted to communicate with a waste heat outflow pipeline 6 through a first communication port, the other end of the water supply main pipeline 101 is adapted to communicate with the water inlet of a user component 5, and water flows in the waste heat outflow pipeline 6; a first heating component 3, including a first heating pump group 303, the first heating pump group 303 is arranged on the water supply main pipeline 101; a return water component 2, including a return water main pipeline 201, one end of the return water main pipeline 201 is adapted to communicate with the waste heat outflow pipeline 6 through a second communication port, the other end of the return water main pipeline 201 is adapted to communicate with the water outlet of the user component 5, the first communication port is located upstream of the second communication port, and a first control valve 601 is arranged on the waste heat outflow pipeline 6 between the first communication port and the second communication port.

[0028] In the heating season, the first control valve 601 is closed, so that the water flow at the first temperature in the waste heat outflow pipeline 6 flows into the first heating pump group 303 through the first water supply main pipeline 101. After the water flow at the second temperature heated by the first heating pump group 303, it flows into the user component 5 through the first water supply main pipeline 101 again. After the user component 5 extracts heat, the water flow at the third temperature flows into the waste heat outflow pipeline 6 through the return water main pipeline 201. The third temperature is lower than the first temperature, and it is discharged into the sea through the drain outlet 602 of the waste heat outflow pipeline 6 until it is discharged into the sea, and the drain outlet 602 is located downstream of the second communication port and the drain outlet 602 communicates with the sea. By setting the first heating component 3, in winter, the temperature of the water flow in the waste heat outflow pipeline 6 is heated, which facilitates the heating of the user component 5 with the water flow at the second temperature. After the user component 5 warms up, the water flow becomes the third temperature. Since the third temperature is lower than the first temperature, the waste heat of the water flow is reused, and the water temperature finally flowing into the sea is lower than the initial water temperature in the waste heat outflow pipeline 6, avoiding the discharge of warm drainage of the initial water flow in the waste heat outflow pipeline 6 and preventing the increase of the water temperature in the water area at the drain outlet 602.

[0029] In one embodiment, as Figure 1 、 Figure 2 、 Figure 3 and Figure 4As shown in the figure, the water supply assembly 1 includes a booster pump 104 and a first switching valve 105. The main water supply pipeline 101 includes a first water supply branch 1011 and a second water supply branch 1012. A first switching valve 105 is provided between the first water supply branch 1011 and the second water supply branch 1012. The first heating assembly 3 includes a first water inlet pipeline 301. The first water supply branch 1011 is located between the waste heat outflow pipeline 6 and the first switching valve 105. A first water inlet pipeline 301 is provided between the first heating pump group 303 and the first switching valve 105. By setting the first switching valve 105, after the water flow in the waste heat outflow pipeline 6 flows through the first water supply branch 1011, it is switched by the first switching valve 105 to make the water flow into the second water supply branch 1012 or the first water inlet pipeline 301 to form different water flow directions to adapt to different usage states. Among them, the water flow in the first water inlet pipeline 301 will enter the first heating pump group 303.

[0030] It should be noted that the water flow in the waste heat outflow pipeline 6 of the present application is a low-grade water flow with a certain temperature discharged from a nuclear power plant, and the designed temperature range of this low-grade water flow is 21-46°C.

[0031] In one embodiment, as Figure 1 、 Figure 2 、 Figure 3 and Figure 4 shown, the water supply assembly 1 further includes an intermediate heat storage tank 103. The main water supply pipeline 101 includes a third water supply branch 1013. The first heating assembly 3 includes a first water outlet pipeline 302. A second water supply branch 1012 is provided between the first switching valve 105 and the intermediate heat storage tank 103. A first water outlet pipeline 302 is provided between the first heating pump group 303 and the intermediate heat storage tank 103. A third water supply branch 1013 is provided between the intermediate heat storage tank 103 and the user assembly 5.

[0032] The intermediate heat storage tank 103 stores and receives hot water flowing out of the first heating pump group 303 for the user assembly 5, or stores and receives the water flow flowing out of the second water supply branch 1012. The third water supply branch 1013 conveys the water flow in the intermediate heat storage tank 103 to the user assembly 5 to provide heat for the user assembly 5.

[0033] In this embodiment, as Figure 1 、 Figure 2 、 Figure 3 and Figure 4As shown, the first heating assembly 3 further includes a first water outlet pipeline 302, which is arranged between the intermediate heat storage tank 103 and the first heating pump group 303, so that the water flowing out of the first heating pump group 303 enters the intermediate heat storage tank 103. It should be noted that, to control the first water inlet pipeline 301 and the first water outlet pipeline 302, a first water inlet valve is provided on the first water inlet pipeline 301, and a first water outlet valve 306 is provided on the first water outlet pipeline 302. Specifically, both the first water inlet valve and the first water outlet valve 306 are solenoid valves.

[0034] In one embodiment, as Figure 1 , Figure 2 , Figure 3 and Figure 4 shown, it further includes a second heating assembly 4. The second heating assembly 4 is connected to the water supply main pipeline 101, and the first heating assembly 3 is located upstream of the second heating assembly 4. The second heating assembly 4 further heats the temperature of the water flow to meet the needs of users, and the first heating assembly 3 is located upstream of the second heating assembly 4 to further increase the temperature on the basis of the heating of the first heating assembly 3.

[0035] In one embodiment, as Figure 1 , Figure 2 , Figure 3 and Figure 4 shown, the second heating assembly 4 includes a second heating pump group 403, a second water inlet pipeline 401 and a second water outlet pipeline 402. The second water inlet pipeline 401 is respectively connected to the intermediate heat storage tank 103 and the second heating pump group 403, and the second water outlet pipeline 402 is respectively connected to the water supply main pipeline 101 and the second heating pump group 403. The connection of the second water inlet pipeline 401 to the intermediate heat storage tank 103 is located upstream of the connection of the second water outlet pipeline 402 to the water supply main pipeline 101.

[0036] The water flow flowing out of the intermediate heat storage tank 103 enters the second heating pump group 403 through the second water inlet pipeline 401, and after being heated by the second heating pump group 403, it flows into the water supply main pipeline 101 through the second water outlet pipeline 402. Since the connection of the second water inlet pipeline 401 to the intermediate heat storage tank 103 is located upstream of the connection of the second water outlet pipeline 402 to the water supply main pipeline 101, the heated water flow flows into the user assembly 5 for heating. It should be noted that, to control the second water inlet pipeline 401 and the second water outlet pipeline 402, a second water inlet valve is provided on the second water inlet pipeline 401, and a second water outlet valve is provided on the second water outlet pipeline 402. Specifically, both the second water inlet valve and the second water outlet valve are solenoid valves.

[0037] In one embodiment, as Figure 1 , Figure 2 , Figure 3 and Figure 4As shown, the return water assembly 2 further includes a circulation pump 202, a second control valve 204, and a second switching valve 203. A circulation pump 202, a second control valve 204, and a second switching valve 203 are sequentially provided on the return water main pipeline 201 from the user assembly 5 towards the waste heat outflow pipeline 6.

[0038] The circulation pump 202 provides the driving force for the water flow in the return water main pipeline 201, and the second control valve 204 controls the opening and closing of the return water main pipeline 201. It should be noted that, as Figure 1 、 Figure 2 and Figure 3 shown, the return water main pipeline 201 further includes a first return water branch 2011, a second return water branch 2012, and a third return water branch 2013. Among them, the first return water branch 2011 is respectively connected to the second return water branch 2012 and the water outlet of the user assembly 5. A second switching valve 203 is provided between the second return water branch 2012 and the third return water branch 2013, and the third return water branch 2013 is communicated with the waste heat outflow pipeline 6.

[0039] In one embodiment, as Figure 1 、 Figure 2 、 Figure 3 and Figure 4 shown, the first heating assembly 3 further includes a third water inlet pipeline 304 and a third water outlet pipeline 305. A third water inlet pipeline 304 is provided between the second switching valve 203 and the first heating pump group 303, and a third water outlet pipeline 305 is provided between the first heating pump group 303 and the return water main pipeline 201.

[0040] The water flow flowing out from the return water main pipeline 201 enters the third water inlet pipeline 304 through the second switching valve 203, then flows into the first heating pump group 303 through the third water inlet pipeline 304, and finally reaches the third return water branch 2013 through the third water outlet pipeline 305, and flows into the waste heat outflow pipeline 6 through the third return water branch 2013. It should be noted that to control the third water inlet pipeline 304 and the third water outlet pipeline 305, a third water inlet valve is provided on the third water inlet pipeline 304, and a third water outlet valve is provided on the third water outlet pipeline 305. Specifically, both the third water inlet valve and the third water outlet valve are solenoid valves.

[0041] In one embodiment, as Figure 1 、 Figure 2 、 Figure 3 and Figure 4As shown, the second heating assembly 4 further includes a fourth water inlet pipeline 404 and a fourth water outlet pipeline 405. A fourth water inlet pipeline 404 is provided between the return water main pipeline 201 and the second heating pump group 403, and a fourth water outlet pipeline 405 is provided between the return water main pipeline 201 and the second heating pump group 403. The connection point of the fourth water inlet pipeline 404 and the return water main pipeline 201 is located upstream of the connection point of the fourth water outlet pipeline 405 and the return water main pipeline 201.

[0042] The water flow flowing out from the user assembly 5 sequentially enters the second heating pump group 403 through the first return water branch 2011 and the fourth water inlet pipeline 404, then flows out from the second heating pump group 403 to the fourth water outlet pipeline 405, and finally reaches the second switching valve 203. It should be noted that, to control the fourth water inlet pipeline 404 and the fourth water outlet pipeline 405, a fourth water inlet valve 406 is provided on the fourth water inlet pipeline 404, and a fourth water outlet valve is provided on the fourth water outlet pipeline 405. Specifically, both the fourth water inlet valve 406 and the fourth water outlet valve are solenoid valves.

[0043] In one embodiment, as Figure 1 、 Figure 2 、 Figure 3 and Figure 4 shown, it further includes a cold water heat exchange plate group 7. The waste heat outflow pipeline 6 is provided with a cold water heat exchange plate group 7, and a cold water heat exchange plate group 7 is provided at the water outlet port of the second communication port and the waste heat outflow pipeline 6. The cold water heat exchange plate group 7 is adapted to be connected to the equipment cooling water supply pipeline 8. The equipment cooling water supply pipeline 8 enters seawater, and heat exchange is realized between the water flow in the waste heat outflow pipeline 6 and the water flow in the equipment cooling water supply pipeline 8 through the cold water heat exchange plate group 7, further reducing the temperature of the water flow in the waste heat outflow pipeline 6 so that the outflowing water flow is basically equal to the seawater temperature.

[0044] To achieve automatic control, it further includes a controller, and the controller is respectively communicatively connected to the first control valve 601, the second control valve 204, the third control valve 102, the first water inlet valve, the first water outlet valve 306, the second water inlet valve, the second water outlet valve, the third water inlet valve, the third water outlet valve, the fourth water inlet valve 406, the fourth water outlet valve, etc.

[0045] In this embodiment, as Figure 1 、 Figure 2 、 Figure 3 and Figure 4As shown, the number of the first heating pump groups 303 of the first heating assembly 3 is three. Among them, each first heating pump group 303 is correspondingly provided with a first water inlet pipeline 301, a first water outlet pipeline 302, a third water inlet pipeline 304 and a third water outlet pipeline 305, and the three first heating pump groups 303 are arranged in parallel and each can operate independently. It should be noted that the water flow flowing out from the first switching valve 105 will be split to the first water inlet pipeline 301 corresponding to each first heating pump group 303; the water flow from the first water outlet pipeline 302 corresponding to each first heating pump group 303 will converge into a first water outlet pipeline 302 and then flow into the intermediate heat storage tank 103; the water flow flowing out from the second switching valve 203 will be split to the third water inlet pipeline 304 corresponding to each first heating pump group 303; the water flow from the third water outlet pipeline 305 corresponding to each first heating pump group will be respectively connected to the third return water branch 2013 and then flow into the waste heat outflow pipeline 6.

[0046] Of course, as an alternative implementation manner, the number of the first heating pump groups 303 of the first heating assembly 3 can also be one, two, four or even more, and different first heating pump groups 303 are arranged in parallel.

[0047] In this embodiment, as Figure 1 , Figure 2 , Figure 3 and Figure 4 shown, the number of the second heating pump groups 403 of the second heating assembly 4 is three. Among them, each second heating pump group 403 is correspondingly provided with a second water inlet pipeline 401, a second water outlet pipeline 402, a fourth water inlet pipeline 404 and a fourth water outlet pipeline 405, and the three second heating pump groups 403 are arranged in parallel and each can operate independently. It should be noted that the water flow flowing out from the intermediate heat storage tank 103 will be split to the second water inlet pipeline 401 corresponding to each second heating pump group 403; the water flow from the second water outlet pipeline 402 corresponding to each second heating pump group 403 will converge into a second water outlet pipeline 402 and then flow into the third water supply branch 1013; the water flow flowing out from the first return water branch 2011 will be split to the fourth water inlet pipeline 404 corresponding to each second heating pump group 403; the water flow from the fourth water outlet pipeline 405 corresponding to each second heating pump group will converge into a fourth water outlet pipeline 405 and then flow into the second return water branch 2012.

[0048] Actually, assuming that the temperature fluctuation on the cold water return side has seasonal fluctuations according to the seawater temperature. Taking a certain nuclear power plant site as an example, the annual seawater temperature fluctuation range is 7 - 32 °C, the public cold water return side fluctuation range is 19 - 48 °C, the summer fluctuation range is about 44 - 48 °C, and the winter fluctuation range is about 19 - 23 °C. Since the temperature fluctuation on the waste heat side is relatively large, a first heat pump unit 303 can be selected according to the heat supply, or two heat pump units (the first heat pump unit 303 and the second heat pump unit 403) can be used in series to recover the heat of the cold water return and produce hot water. The first heat pump unit 303 supplies and returns water directly to the user without passing through the second heat pump unit 403 through the third control valve 102 and the second control valve 204. The second heat pump unit 403 takes the heat side to supply and return water directly from the waste heat source without passing through the first heat pump unit 303 through the first switching valve 105 and the second switching valve 203, thereby realizing the independence of equipment operation under different heating conditions.

[0049] Taking a certain nuclear power plant site as an example, in summer, the cold water return temperature is 46 °C, and in winter, the cold water return temperature is 21 °C. The total remaining heat in the public loop is 26 MW, and the flow rate is 2100 m 3 / h. The heat absorption end load of the heat pump unit is 12 MW, and the heat production is about 30 MW. Since the heat load and flow rate of the nuclear power unit under each working condition do not differ much, this part of the waste heat can be stably recovered.

[0050] Of course, as an alternative implementation, the number of the second heat pump units 403 of the first heating component 3 can also be one, two, four or even more, and different second heat pump units 403 are arranged in parallel.

[0051] Embodiment 1

[0052] As Figure 2 shown, a method for using a waste heat recovery system for equipment cooling water in a nuclear power plant, applicable to ordinary heating in winter, includes the following steps:

[0053] 1) The controller closes the first control valve 601, the second water inlet valve, the second water outlet valve, the fourth water inlet valve 406, and the fourth water outlet valve, opens the first water inlet valve, the first water outlet valve 306, the third water inlet valve, the third water outlet valve, and the second control valve 204. The first switching valve 105 closes the second water supply branch 1012 and opens the first water inlet pipeline 301, and the second switching valve 203 opens the third water inlet pipeline 304;

[0054] 2) Water at the first temperature flows from the waste heat outflow pipe 6, and the water flows through the first water supply branch 1011 and the first water inlet pipe 301 into the first heating pump unit 303, and is heated by the first heating pump unit 303 to reach the second temperature. After the water flows out of the first heating pump unit 303, it flows through the first water outlet pipe 302 into the intermediate heat storage tank 103, and then from the intermediate heat storage tank 103 to the user component 5 through the third water supply branch 1013. After the heating of the user component 5 is completed, the water The flow temperature is the third temperature. The water flowing out from the water outlet of the user component 5 passes through the first return water branch 2011, the second return water branch 2012, and then enters the first heating pump group 303 through the third water inlet pipe 304. Then it flows out from the first heating pump group 303 through the third outlet pipe 305 and merges into the third return water branch 2013 and flows into the waste heat outflow pipe 6. The water flows through the heat exchange plate group 7 and exchanges heat with the water in the equipment cooling water supply pipe 8 to reach the fourth temperature, and is finally discharged into the sea.

[0055] It should be noted that when the water flow of the third water inlet pipe 304 enters the first heat pump group 303, it will not be heated, and will maintain the third temperature to flow into the waste heat outflow pipe 6. In this embodiment, the first heat pump group 303 is a mechanical compression electric heat pump group, which is divided into four major components, namely: evaporator, condenser, compressor and expansion valve. The refrigerant circulates in the above four components to achieve energy consumption by consuming electrical energy. The evaporator and condenser are shell and tube heat exchangers, one side is water and the other side is refrigerant. Among them, the two water supply circuits on the waste heat side pass through the water side of the evaporator component separately, one side supplies water to the evaporator, and returns to the equipment cooling water after cooling; the two water supply and return circuits on the user side pass through the water side of the condenser separately, one side is supplied to the user, and the other side returns to the condenser. Therefore, the third water inlet pipe 304 still needs to return to the first heat pump group 303. It should be noted that the principles of the first heat pump group 303 and the second heat pump group 403 are the same. The first heating pump group 303 increases the water temperature of water entering from the first water inlet pipe 301, so that the water temperature of the first water outlet pipe 302 is higher than the water temperature of the first water inlet pipe 301; the first heating pump group 303 reduces the water temperature of water entering from the third water inlet pipe 304, so that the water temperature of the third water outlet pipe 305 is lower than the water temperature of the third water inlet pipe 304.

[0056] During the whole process, the booster pump 104 provides the circulating power. When water replenishment is required, the first water replenishment pipeline 9 replenishes water to the first return water branch 2011. The first temperature is lower than the second temperature, the third temperature is lower than the first temperature, the fourth temperature is lower than the third temperature, and the fourth temperature is equal to the seawater temperature, so as to make full use of the heat of the water flow in the waste heat outflow pipeline 6, so that the fourth temperature of the water finally discharged into the sea is lower than the first temperature of the water flow in the waste heat outflow pipeline 6, thus avoiding increasing the temperature of the surrounding seawater due to the discharge of warm drainage. During the whole process, a first heating pump group 303 produces hot water at about 70 °C to meet the heating demand under normal working conditions. The cold water waste heat utilization rate is set at 46%, the heat production per unit is about 10 MW, and the COP (performance index) of the heat pump unit is about 3.5 - 4.5.

[0057] Embodiment 2

[0058] As Figure 3 shown, a method for using a waste heat recovery system for equipment cooling water in a nuclear power plant, which is applicable to the utilization of waste heat from seawater desalination in summer, includes the following steps:

[0059] 1) Close the first control valve 601, the second control valve 204, the third control valve 102, the first water inlet valve, the first water outlet valve 306, the third water inlet valve and the third water outlet valve, open the second water inlet valve, the second water outlet valve, the fourth water inlet valve 406 and the fourth water outlet valve. The first switching valve 105 opens the second water supply branch 1012, and the second switching valve 203 opens the third return water branch 2013;

[0060] 2) Water flow with the first temperature flows from the waste heat outflow pipeline 6, and the water flows through the first water supply branch 1011 and the second water supply branch 1012 into the intermediate heat storage tank 103. The water flowing out of the intermediate heat storage tank 103 flows into the second heating pump group 403 through the second water inlet pipeline 401, is heated to the second temperature by the second heating pump group 403, and then is transported to the user assembly 5 through the second water outlet pipeline 402. After the waste heat from seawater desalination is utilized, the water flow with the third temperature flowing out of the user assembly 5 sequentially flows through the first return water branch 2011 and the fourth water inlet pipeline 404 into the second heating pump group 403. The water flowing out of the second heating pump group 403 sequentially flows through the fourth water outlet pipeline 405 and the third return water branch 2013 into the waste heat outflow pipeline 6. The water flow exchanges heat with the water flow in the equipment cooling water supply pipeline 8 through the heat exchange plate group 7 and reaches the fourth temperature, and finally is discharged into the sea.

[0061] It should be noted that when the water flow in the fourth water inlet pipe 404 enters the second heating pump group 403, it will not be heated and will flow into the waste heat outlet pipe 6 at the third temperature. During the whole process, the booster pump 104 and the circulation pump 202 provide the circulation power. When water replenishment is required, the first water replenishment pipe 9 replenishes water to the first return water branch 2011. The first temperature is lower than the second temperature, the third temperature is lower than the first temperature, the fourth temperature is lower than the third temperature, and the fourth temperature is equal to the seawater temperature, so as to make full use of the heat of the water temperature in the waste heat outlet pipe 6, so that the fourth temperature of the water flow finally discharged into the sea is lower than the first temperature of the water flow in the waste heat outlet pipe 6, thus avoiding the increase of the temperature of the surrounding seawater due to the discharge of warm drainage. During the whole process, a second heating pump group 403 produces hot water at about 90 °C to meet the heat demand for the seawater desalination process. The cold water waste heat utilization rate is 46%, the single heating capacity is about 10 MW, and the COP (performance index) of the heat pump unit is about 6.

[0062] Embodiment 3

[0063] As Figure 4 shown, a method for using a waste heat recovery system for the cooling water of nuclear power plant equipment, which is applicable to peak heating in winter / waste heat utilization in winter seawater desalination, includes the following steps:

[0064] 1) Close the first control valve 601, the second control valve 204, and the third control valve 102, open the first water inlet valve, the first water outlet valve 306, the second water inlet valve, the second water outlet valve, the third water inlet valve, the third water outlet valve, the fourth water inlet valve 406, and the fourth water outlet valve. The first switching valve 105 closes the second water supply branch 1012 and opens the first water inlet pipe 301, and the second switching valve 203 opens the third water inlet pipe 304;

[0065] 2) Water flow with a first temperature flows out from the waste heat outflow pipeline 6, passes through the first water supply branch 1011 and the first water inlet pipeline 301, and enters the first heating pump group 303. After being heated by the first heating pump group 303, it reaches a second temperature. The water flows out of the first heating pump group 303, passes through the first water outlet pipeline 302, and enters the intermediate heat storage tank 103. Then, it enters the second heating pump group 403 from the intermediate heat storage tank 103 through the second water inlet pipeline 401. After being heated by the second heating pump group 403, it reaches a third temperature. The water flow at the third temperature flows into the user assembly 5 through the second water outlet pipeline 402. This water flow at the third temperature is used for winter seawater desalination or winter peak heating. After the user assembly 5 finishes, the water temperature is the fourth temperature. The water flowing out from the water outlet of the user assembly 5 passes through the first return water branch 2011 and the fourth water inlet pipeline 404 and reaches the second heating pump group 403. Then, it flows into the first heating pump group 303 from the second heating pump group 403 through the fourth water outlet pipeline 405 and the third water inlet pipeline 304. Then, it flows out of the first heating pump group 303, passes through the third water outlet pipeline 305, and joins the third return water branch 2013 and flows into the waste heat outflow pipeline 6. The water flow exchanges heat with the water flow in the equipment cooling water supply pipeline 8 through the heat exchange plate group 7 and reaches a fifth temperature, and finally is discharged into the sea.

[0066] It should be noted that when the water flow entering the first heating pump group 303 from the third water inlet pipeline 304 is cooled down, and the water flow entering the second heating pump group 403 from the fourth water inlet pipeline 404 is cooled down, it will flow into the waste heat outflow pipeline 6 at a temperature lower than the fourth temperature. During the whole process, the booster pump 104, the circulation pump 202, and the intermediate pump 407 provide the circulation power. When water replenishment is needed, the first water replenishment pipeline 9 replenishes water to the first return water branch 2011, and the second water replenishment pipeline 10 replenishes water to the third water inlet pipeline 304. The first temperature is less than the second temperature, the second temperature is less than the third temperature, the fourth temperature is less than the first temperature, the fifth temperature is less than the fourth temperature, and the fifth temperature is equal to the seawater temperature. Thus, the heat in the waste heat outflow pipeline 6 is fully utilized, so that the fifth temperature of the water flow finally discharged into the sea is lower than the first temperature of the water flow in the waste heat outflow pipeline 6, thereby avoiding increasing the temperature of the surrounding seawater due to the discharge of warm water. During the whole process, about 80°C - 90°C hot water is produced by the series connection of one first heating pump group 303 and the second heating pump group 403 to meet the heating demand under peak load conditions and the process heat demand of seawater desalination users. The cold water waste heat utilization rate is set at 46%, the heat production per unit is about 10 MW, and the COP (performance index) of the heat pump unit is about 4 - 5.

[0067] The waste heat recovery system for the equipment cooling water of a nuclear power plant provided by this application has the following advantages: (1) On the basis of ensuring the normal execution of the functions of the equipment cooling water system of the nuclear power plant, the waste heat of the equipment cooling water of the nuclear power plant is recovered and utilized, reducing the heat discharged into the sea, reducing the operating power of the seawater pump, and reducing energy waste; (2) The grade of the waste heat energy is improved through heat pump technology, which can supplement domestic hot water, heating for the plant area, and heat for the seawater desalination process, promoting the cascaded utilization of energy and improving the low-carbon performance of the nuclear power plant; (3) In winter, it can replace the steam extraction heat exchange heating of the nuclear power plant. The total power consumption is less than the total power consumption of steam extraction heating, there is no steam extraction volume, and it has no impact on the nuclear power generation power. In summer, it can be used as the heat source for the seawater desalination process; (4) According to the temperature of the return water of the cooling water and the heat demand of the users in different seasons, a single heating pump group or a double heating pump group can be operated. On the premise of not affecting the functions of the equipment cooling water system, part of the waste heat is recovered and utilized, solving the problem of warm water discharge caused by the direct discharge of the return water of the equipment cooling water while providing heating (domestic hot water and heating) for the nuclear power plant area and the heat source for the seawater desalination process.

[0068] Although the embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations fall within the scope defined by the appended claims.

Claims

1. A waste heat recovery system for the equipment cooling water of a nuclear power plant, characterized in that, Comprising: A water supply assembly (1), the water supply assembly (1) includes a main water supply pipeline (101), one end of the main water supply pipeline (101) is adapted to communicate with the waste heat outflow pipeline (6) through a first communication port, the other end of the main water supply pipeline (101) is adapted to communicate with the water inlet of the user assembly (5), and there is water flowing in the waste heat outflow pipeline (6); A first heating assembly (3), the first heating assembly (3) includes a first heating pump group (303), and the first heating pump group (303) is arranged on the main water supply pipeline (101); A return water assembly (2), the return water assembly (2) includes a main return water pipeline (201), one end of the main return water pipeline (201) is adapted to communicate with the waste heat outflow pipeline (6) through a second communication port, the other end of the main return water pipeline (201) is adapted to communicate with the water outlet of the user assembly (5), the first communication port is located upstream of the second communication port, and a first control valve (601) is provided on the waste heat outflow pipeline (6) between the first communication port and the second communication port.

2. The waste heat recovery system for the cooling water of nuclear power plant equipment according to claim 1, characterized in that, The water supply assembly (1) includes a booster pump (104) and a first switching valve (105), the main water supply pipeline (101) includes a first water supply branch (1011) and a second water supply branch (1012), the first switching valve (105) is provided between the first water supply branch (1011) and the second water supply branch (1012), the first heating assembly (3) includes a first water inlet pipeline (301), the first water supply branch (1011) is located between the waste heat outflow pipeline (6) and the first switching valve (105), and the first water inlet pipeline (301) is provided between the first heating pump group (303) and the first switching valve (105).

3. The waste heat recovery system for the cooling water of nuclear power plant equipment according to claim 2, wherein, The water supply assembly (1) further includes an intermediate heat storage tank (103), the main water supply pipeline (101) includes a third water supply branch (1013), the first heating assembly (3) includes a first water outlet pipeline (302), the second water supply branch (1012) is provided between the first switching valve (105) and the intermediate heat storage tank (103), the first water outlet pipeline (302) is provided between the first heating pump group (303) and the intermediate heat storage tank (103), and the third water supply branch (1013) is provided between the intermediate heat storage tank (103) and the user assembly (5).

4. The low-grade waste heat recovery system for a nuclear power plant according to any one of claims 1 to 3, characterized in that, It further includes a second heating assembly (4), the second heating assembly (4) is communicated with the main water supply pipeline (101), and the first heating assembly (3) is located upstream of the second heating assembly (4).

5. The waste heat recovery system for the cooling water of nuclear power plant equipment according to claim 4, characterized in that, The second heating component (4) includes a second heating pump group (403), a second water inlet pipeline (401), and a second water outlet pipeline (402). The second water inlet pipeline (401) is respectively communicated with the intermediate heat storage tank (103) and the second heating pump group (403), and the second water outlet pipeline (402) is respectively communicated with the main water supply pipeline (101) and the second heating pump group (403). The connection between the second water inlet pipeline (401) and the intermediate heat storage tank (103) is located upstream of the connection between the second water outlet pipeline (402) and the main water supply pipeline (101).

6. The waste heat recovery system for the cooling water of nuclear power plant equipment according to claim 5, wherein, The return water component (2) further includes a circulation pump (202), a second control valve (204), and a second switching valve (203). The circulation pump (202), the second control valve (204), and the second switching valve (203) are sequentially arranged on the return water main pipeline (201) from the user component (5) towards the waste heat outflow pipeline (6) of the return water main pipeline (201).

7. The waste heat recovery system for the cooling water of nuclear power plant equipment according to claim 6, wherein, The first heating component (3) further includes a third water inlet pipeline (304) and a third water outlet pipeline (305). The third water inlet pipeline (304) is arranged between the second switching valve (203) and the first heating pump group (303), and the third water outlet pipeline (305) is arranged between the first heating pump group (303) and the return water main pipeline (201).

8. The waste heat recovery system for the cooling water of nuclear power plant equipment according to claim 7, characterized in that, The second heating component (4) further includes a fourth water inlet pipeline (404) and a fourth water outlet pipeline (405). The fourth water inlet pipeline (404) is arranged between the return water main pipeline (201) and the second heating pump group (403), and the fourth water outlet pipeline (405) is arranged between the return water main pipeline (201) and the second heating pump group (403). The connection between the fourth water inlet pipeline (404) and the return water main pipeline (201) is located upstream of the connection between the fourth water outlet pipeline (405) and the return water main pipeline (201).

9. The waste heat recovery system for the cooling water of nuclear power plant equipment according to claim 8, characterized in that, It further includes a cold water heat exchange plate group (7). The cold water heat exchange plate group (7) is arranged on the waste heat outflow pipeline (6), and the cold water heat exchange plate group (7) is arranged at the water outlet port of the second communication port and the waste heat outflow pipeline (6). The cold water heat exchange plate group (7) is suitable for being communicated with the equipment cooling water supply pipeline (8).

10. A method for using a waste heat recovery system for cooling water of nuclear power plant equipment, which is used for the waste heat recovery system for cooling water of nuclear power plant equipment described in claim 1, characterized in that, In the heating season, the first control valve (601) is closed, so that the water flow at the first temperature in the waste heat outflow pipeline (6) flows through the first main water supply pipeline (101) into the first heating pump group (303). After being heated by the first heating pump group (303), the water flow at the second temperature then flows through the first main water supply pipeline (101) into the user component (5). After the user component (5) extracts heat, the water flow at the third temperature flows through the return water main pipeline (201) and then flows back into the waste heat outflow pipeline (6). The third temperature is lower than the first temperature until it is discharged.

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